Reliability of the commercially available Cigua-Check? test kits to identify ciguateric fish was evaluated by assessing the uniformity of conclusions by multiple readers examining identical sticks. One hundred and eig...Reliability of the commercially available Cigua-Check? test kits to identify ciguateric fish was evaluated by assessing the uniformity of conclusions by multiple readers examining identical sticks. One hundred and eighty-eight samples of two types of reef fish were tested for ciguatera using Cigua-Check? test strips. Paired subsamples of all specimens were also analyzed via the more rigorous N2a neuroblastoma mouse bioassay that is specific for aberration of Na+-channel activity that is presumptive for ciguatera fish poisoning. In a double blind trial, four individuals visually examined identical Cigua-Check? strips to conclude whether the samples were positive or negative for ciguatera. Of the 121 samples that were shown to be positively ciguatoxic via bioassay, the four strip readers were in agreement in concluding positive ciguateric status in 9.9% of the samples;these four readers concluded these positive samples were negative for ciguatera in 26.2% of these bioassay-positive samples. Of the 67 samples that were shown in N2a bioassay to be negatively ciguatoxic, the four readers were in agreement in concluding a negative ciguateric status in 26.9% of the samples;these four strip readers concluded these same samples were positive for ciguatera in 14.9% of these negative samples. The low levels of uniform conclusions among readers examining identical test strips, and the low frequency of agreement with the correct ciguateric status as shown by separate N2a neuroblastoma analyses indicate severe short-comings in the reliability of these test kits to accurately reflect the ciguateric status of samples. The level of uncertainty associated with Cigua-Check? test kits indicate a continuing need for improvement of a simple, rapid, and reliable means to identify ciguateric fish.展开更多
文摘Reliability of the commercially available Cigua-Check? test kits to identify ciguateric fish was evaluated by assessing the uniformity of conclusions by multiple readers examining identical sticks. One hundred and eighty-eight samples of two types of reef fish were tested for ciguatera using Cigua-Check? test strips. Paired subsamples of all specimens were also analyzed via the more rigorous N2a neuroblastoma mouse bioassay that is specific for aberration of Na+-channel activity that is presumptive for ciguatera fish poisoning. In a double blind trial, four individuals visually examined identical Cigua-Check? strips to conclude whether the samples were positive or negative for ciguatera. Of the 121 samples that were shown to be positively ciguatoxic via bioassay, the four strip readers were in agreement in concluding positive ciguateric status in 9.9% of the samples;these four readers concluded these positive samples were negative for ciguatera in 26.2% of these bioassay-positive samples. Of the 67 samples that were shown in N2a bioassay to be negatively ciguatoxic, the four readers were in agreement in concluding a negative ciguateric status in 26.9% of the samples;these four strip readers concluded these same samples were positive for ciguatera in 14.9% of these negative samples. The low levels of uniform conclusions among readers examining identical test strips, and the low frequency of agreement with the correct ciguateric status as shown by separate N2a neuroblastoma analyses indicate severe short-comings in the reliability of these test kits to accurately reflect the ciguateric status of samples. The level of uncertainty associated with Cigua-Check? test kits indicate a continuing need for improvement of a simple, rapid, and reliable means to identify ciguateric fish.
文摘有许多方法可以让我们从被选择(selected)而不是被操纵(manipulate)的少量案例中推论出因果关系。首先,本文考察了'可比案例策略'(comparable-cases strategy)的发展以及'比较方法即是可比案例策略'这一论调。其次,本文将考察另一种比较方法,即由密尔提出的'求同法'。这种方法不仅能并已经被有效地运用于比较政治学中的调查(survey)研究中,而且这种使用完全未受其方法论上固有的所缺陷影响。简单地说,上述两种方法要求选择案例的标准应是相似性(similarity)或者是相异性(contrast)。不过,若与'共变法'(method of concomitant variation)相比,这两种定性的比较方法即便在同时被使用的时候所起到的作用仍显不足,所以,本文便又为比较研究学者提供了第三种策略。这个策略曾多次被涂尔干所使用,但却又因下述理由而明显被忽视:学者们总是将其(与求同法一道)简化为一种单一的、基于可比案例的比较方法。
